1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a computer program product.
2. Description of the Related Art
In recent years, various colored characters and color images are used in a document created by individuals or companies along with the development of a color image output technology such as display or printing of a color image. In such a document, a color itself is often given important information, such as performing color-coding by colored characters or a plurality of colors for a sign to draw attention or grouping of a graph. Therefore, in order to correctly understand these contents of the document, it is required to have an ability to distinguish a difference of colors used in the document in addition to an ability to recognize characters and images.
A document, in which such various colors are used, is easily understood by people having a common color vision; however, the same is not always true for people having a color vision property different from the common color vision. According to a physiological and medical research on a human color vision, it is ever known that some types exist as the color vision property such as red-green blindness with which red and green are difficult to distinguish or cannot distinguish, yellow-blue blindness, and total color-blindness. Recently, the CUDO (NPO Color Universal Design Organization) advocates to describe people having a C-type (initial letter of Common) color vision as a common color vision and describe other people having a weak portion in recognizing color as colorblind people by using type names of the color vision such as the C-type instead of drawing a line by whether the color vision is normal or abnormal. The types of the color vision include strong and weak P-types (Protanope) (corresponding to red-green blindness or colorblind), strong and weak D-types (Deuteranope) (corresponding to red-green blindness or colorblind), a T-type (Tritanope) (corresponding to yellow-blue blindness), and an A-type (Achromat) (corresponding to total color-blindness) other than the C-type.
Conventionally, a load for document creation for people having such various color vision properties to easily distinguish colors becomes extremely large and a degree of latitude in design is limited in some cases. For example, a typical situation is assumed, in which the common color vision people create an electronic document for presentation, which is color-printed and distributed, and the electronic document is projected on a screen to make the presentation. In this case, for example, in a typical office application software for creating a graph, a color scheme is automatically applied to each element, so that a user needs to designate a color for each element again in some cases.
Moreover, typically, a color range to be reproduced becomes different between different image output apparatuses such as a printing apparatus including a color printer and a projector that projects an image on a screen. Therefore, even if the color scheme is applied so that a color difference can be easily recognized on a printing, the colors sometimes change on a projected image, so that distinction of the colors is not improved in some cases.
For solving such a problem, a color-sample selecting apparatus is proposed that facilitates the common color vision people who make a document to select a color that is not easily confused by the colorblind people at the time the document made by controlling such that a color easily confused by the colorblind people cannot be selected. Moreover, a display system is proposed that displays an image simulating a view of the colorblind people so that the common color vision people can recognize a portion that is difficult to distinguish for the colorblind people.
For example, Japanese Patent Application Laid-open No. 2006-350066 discloses a color-sample selecting apparatus that, when a color to be used in a document or a design is selected, controls not to select a combination of a color that could easily confuse the colorblind people. Moreover, Japanese Patent Application Laid-open No. 2007-334053 discloses a display system that displays an image simulating a view that the colorblind people see, for causing the common color vision people to recognize a difficulty of distinguishing colors for the colorblind people.
However, even the methods, such as those disclosed in Japanese Patent Application Laid-open No. 2006-350066 and Japanese Patent Application Laid-open No. 2007-334053, have problems that it is difficult for the common color vision people to determine whether the colorblind people can distinguish, and a load for document creation cannot be improved in some cases. For example, the display system, such as disclosed in Japanese Patent Application Laid-open No. 2007-334053, displays a color vision simulation image. However, it is known that a hue is different depending on a simulation rule and the color vision property is individually different even among the common color vision people. Therefore, when a color is slightly different in the result of the color vision simulation, in some cases the common color vision people are difficult to determine whether it is difficult for the colorblind people to distinguish the color difference. Moreover, when the common color vision people determine that it is difficult for the colorblind people to distinguish the color difference, problems arise, such as limitation in design and a trouble of changing the color scheme, i.e., avoiding use of a color that is difficult for the colorblind people to distinguish or replacing with a different color.